But in Japan, robots aren't the enemy. They are the good guys. They are also getting smaller, a lot smaller.

Scientists in Tokyo have invented what may be the world's tiniest robot, measuring just 10 millimeters long and weighing less than half a gram.

Researchers hope to use the micro-robots to repair equipment in nuclear and thermal plants. The device could maneuver in tight crevices or lock onto damaged parts.

The robots, which can crawl into the tiniest gaps around bundles of pipes, are expected to speed up inspection and repairs at electric and nuclear power plants because they can be sent in while the plants keep running.

Scientists are working to add new functions to them so the robots can climb up and down a pipe while connected to other machines. They also plan to develop robots with motors and problem-detecting sensors.

U.S. government engineers have developed miniature surveillance robots that can hover around a room. And NASA engineers are working on a "spacecraft on a chip," says Barry Hebert, manager of
micro- and nano-technology development at NASA's Jet Propulsion Laboratory.

"That means miniaturizing every part of a spacecraft, from brains to instruments to devices," he says. "Right now we've got systems on a chip and right now we're putting the components together to do that."

But for now, the Japanese may hold the record for the tiniest robot in operation.

The idea for tiny robots began 10 years ago as a cooperative research project between the government and Mitsubishi Electric Corp., Sumitomo Electric Industries Ltd. and Matsushita Research Institute Tokyo, Inc. under the government's 25 billion yen ($206 million) "micro-machine" project, said Koji Hirose, spokesman for the Ministry of International Trade and Industry.

Despite the big plans, the micro-machines are still years from widespread use.